Brandon Adams, over at Reformed Libertarian, writes:
To them also, as a body politic, He gave sundry judicial laws, which expired together with the State of that people; not obliging under any now, further than the general equity thereof may require.
Many reformed Christians today, who have grown tired of today’s moral relativism, turn to WCF 19.4 in an effort to develop a political philosophy. The Law of God, they say, must be our only standard. We must follow God’s law, or man’s law. And God has given a rather detailed list of how that law applies to states in the Mosaic Law. Of course, those laws were particular to Israel, but if we change the details, the laws are still God’s ideal for states. So, we exchange language about the land of Canaan for the land of California, and “voilla!” we’re left with the “general equity” of any give Mosaic law.
The problem, however, is that is not the meaning of WCF 19.4. The 2nd London Baptist Confession helpfully phrases it slightly differently:
To them also he gave sundry judicial laws, which expired together with the state of that people, not obliging any now by virtue of that institution; their general equity only being of moral use. *1 Cor. 9:8-10
LBCF clarifies that judicial laws do not oblige anyone by virtue of their being part of the Mosaic law. It is only their general equity that is of broadly moral use. But if general equity does not mean swapping “California” for “Canaan”, what does it mean?
The confession’s position followed Calvin, and others.
It is a fact that the law of God which we call the moral law is nothing else than a testimony of natural law and of that conscience which God has engraved upon the minds of men. Consequently, the entire scheme of this equity of which we are now speaking has been prescribed in it. Hence, this equity alone must be the goal and rule and limit of all laws. (Institutes IV.xx.15-16)
The equity that an old covenant judicial law might possess does not come from the particular old covenant judicial law itself. It is simply an application of moral/natural/universal law to Israel’s unique, covenantally conditioned national life. So, there may be principles in particular old covenant judicial laws that transcend the old covenant. But the temporary law does not establish what constitutes equity. It is a unique illustration/application of it. Hence, the equity predates and even transcends the old covenant.
The general equity was the moral law that the judicial laws, unique to Israel, were based on. Thus it is the moral law that continues to be of use. The judicial laws only help provide us with specific examples of how the moral law was applied to Israel. Therefore, we do not reason from Canaan to California (1 step), but from Canaan to moral law to California (2 steps).
This can be better understood by recognizing the distinction between positive law and moral law…